Engine starter



. June 11, 1940. Jfw. Fnz GERALD '2,203,724-

ENGINE STARTER Filed Feb. 20, 1939 2 Sheets-Sheet l June 11, 1940. J. w. FITZGERALD 2,203,724

\ ENGINE STARTER Filed Feb. 2o, 1939 2 sheets-sheet 2 'Patented June 1l, l;-

PATENT .oi-Fica ENGINE vstralt'rlzit John W. Fitz Gerald, Milwaukee, Wis., assignor to Briggs t Stratton Corporation, Milwaukee,

Wis., a corporation of Delaware Application February zo, 193s, serial No. 257,43'1

3 Claims.

This invention relates to engine starters, and refers particularly to starters of the Bendix" type.

One of the objects of the presentinvention is to provide a starter of unitary construction, and one which does not require a separatepinion stop to be secured to the motor shaft.

Another object of this invention is to` provide a starter which employs a rubber cushioning collar 4 10 to transmit the torque from the motor shaft to the pinion, and also absorbs the shock incidental to improper meshing of the gears. Another object of this invention is to provide an engine starter of 'the 'character described l5 wherein the translation of the pinion to and from its operativeposltion is effected through a cam connection `as distinguished from the more conventional use of screw threads.

With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described, and more particularly dened by the appended claims, it being understood that such changes in theprecise embodiment of the herein disclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one- Figure 3 is a view similar to Figure 1. showing the parts in the positions they assume during the actual transmission of the driving force to `lthe engine ring gear; l

Figure 4 is substantially a longitudinal sectional view taken through Figurel on the plane' of the line L4; and

Figure 5 is a perspective view ofthe pinion actuator and the rubber driving element shown v separated from the rest of the structure and from each other.

Referring now particularly to the accompanying drawings in which like numerals indicate like parts, the numeral 5 designates the motor shaft of the starter, which, as is customary, extends past the ring gear t of the engine. The

starter mechanism, indicated generally by the numeral l, is applied to the shaft as a unit and comprises a pinion 8 slidably mounted o n the shaft for longitudinal movement into and out of mesh with the engine ring gear. 5

Extending outwardly from the pinion is a. sleeve 9which, in the inoperative position of the pinion, has its outer end adjacent toi'a fixed abutment in the form of a collar il) which is secured on the shaft. The pinion sleeve 9 mounts 10 two spiral cams ll andsl2 between which a correspondingly cam-shaped pinion actuator I3 is interposed. To enable assembly, the outer spiral cam l2 .s brazedgor otherwise secured to the sleeve 9 after the pinion actuator has been ap- 15 plied.

The actuator i3 -is tubular and is freely rotat- `able and slideable on the sleeve 9 but has no endwise `motion with relation to the Spiral cams Il and l2.` It is only through relative rotation be- 2n tween the actuator and the sleeve that longitudinal motion is permitted the actuator.

Rotationn is imparted from the shaft `to the pinion actuator to effect translation of the pinion into' mesh with the ring gear through a torsion- 25 ally and endwise resilient driving connection, in-

l dicated generally by the numeral i4.

This driving connection comprises a rubber collar I5 interposed between a flange i6 on the collar Iland a flange I1 on the pinion actuator. :m A cylindrical shell i8 having its edges turned over the flanges holds the same against spreading beyond a predetermined distance to maintain the rubber collar under a degree of compression.

vulcanized to the opposite faces or ends of the 35 'rubber collar are metal washers I 9, the outer f' faces of which have driving lugs 20 projecting therefrom to engage in recesses or holes 2l in the adjacent flanges. Hence, each flange is positively connected with the adjacent face of the qu rubber collar which is important in this construction inasmuch as the driving torque is transmitted without increasing the compression' of the rubber collar.

In operation, the initial rotation of the actuator I3 by virtue of its resilient driving connec tion with the shaft propels the pinion forwardly into mesh with the ring gear. 'I'he forward propulsion of the pinion is limited by the cam connection between the pinion sleeve and the pinion '60 as at 22 in Figure 3.

When the engine begins to operate under its es own power, the overrunning action of the pinionl through the cam connection retracts the pinion in the customary manner.

It is to be observed that when the load of the engine is taken up, there is a positive driving connection from the pinion actuator to the pinion through the abutting ends 22 of the cams. as shown irll Figure 3, but the actual picking up of the load is cushioned through the torsional resiliency of the rubbercollar.

The endwise resiliency of the collar absorbs shock incidental to improper meshing of the gears, as shown in Figure 2. In this instance, the obstruction of forward propulsion of' the pinion, through the action ofthe cam connection between the pinion sleeve and the actuator. causes the anges I6 and I1 to move toward each other to compress therubber collar. This action continues until the friction between the inclined faces of the complementary cams overl cornes the friction at the abutting teeth. whereupon the pinion is turned sufficiently to effect proper meshing.

- its operative position uponrelative rotation be- From the foregoing description taken in connection with the accompanying drawings, it will be readily apparent that this invention provides an engine starter which is capable of being mounted n the motor shaft as a complete unit, and that no separate stop is required to limit the motion of the pinion toward the ring gear.

What I claim as my invention is:

1. In an engine starter: a power shaft; a pinion movable along the shaft to and from an operative position in which it meshes with` the ring' gear of an engine; a sleeve extending from said pinion; an actuator for the pinion freely encircling a medial portion of the sleeve; a flanged abutment secured to the shaft adjacent to the end o f the sleeve; an annular flange on the actuator medially of its ends; a resilient driving connection between the shaft and the pinion actuator including a rubber collarv confined between said flanges and providing the sole driving connection between the shaft and.- the actu- -.ator; and a separate cam connection between the actuator and the.plnion sleeve atk eachsidek of the` actuator ange operable sequentially to move the pinion along the shaft to and from tween the pinion and its actuator,l one of said cam connections including means for arresting movement of the pinion toward its operative position and for drivingly connecting the pinion with the actuator for rotation therewith.

2. In an engine starter: a power shaft; a pinion movable along the shaft to and from an operative position in which it meshes with the ring gear of an engine; a sleeve extending from one end of said pinion; separate spaced apart cam surfaces on said sleeve; a substantially tubu' lar pinion actuator encircling the sleeve and confined between the cam surfaces thereof; a cam connection between each end of the actuator and the adjacent cam surface of the sleeve preventing axial movement of the pinion with respect to the actuator except upon 4relative rotation between said parts, one of said cam connections being operable to propel the pinion to its operative position in which it meshes with the ring gear, and the other cam connection being operable to retract the pinion upon starting of the engine; co-operating means included in said other camconnection forflimiting relative rotation between the actuator and the pinion and for drivingly connecting the pinion with the actuator for rotation therewith; and a torsionally and endwise resilient driving connection between the shaft and the actuator. -3.`In an engine starter: a power shaft; a pinion movable along the shaft` to and from an operative position in which it meshes with the ring gear of an engine; a sleeveon the pinion; separate endwise spaced apart cam surfaces on said sleeve; a substantially tubular pinion actuator encircling the sleevev and conned between the cam surfaces thereof; a. cam connection between each end of the actuator and the adjacent cam surface of the sleeve, said cam surfaces be- -ing engaged at all times so that no lost motion exists between the pinion and the actuator whereby axial movement vof the piniony with respect to the actuator is possible only upon relative rotation between said parts, said cam connections being sequentially operable to propel the pinion to itsoperative position'infwhich it meshes with the ring gear and to retract ythe pinion upon 'starting Aof the engine;vv andal torsionally and endwise resilientdriving connection between the shaft and the actuator.

JOHN W. FITZ GERALD. 

